The present invention relates generally to arm powered vehicles, specifically to vehicles propelled by handles mounted on the inside of the right and left drive wheels. The rider uses a circular motion for propulsion.
Most racing wheelchairs are propelled by pushrims on the outside of the two drive wheels. The rider reaches back and puts the heels of their hands on the pushrims of the two drive wheels. They then push the pushrims down as the wheels rotate.
There are several weaknesses to this design. First, this design is inefficient, having considerable lost and wasted motion. The power stroke is only approximately one fifth of a revolution requiring one""s hands and arms to return to the starting position after each power stroke. During the return stroke, energy is consumed but not transmitted to the drive wheels as the hands return empty to the original position. Not only is this inefficient, but during this time the wheelchair is out of control and can be particularly dangerous when ascending or descending a ramp or other irregular terrain. Second, this type of motion can also lead to repetitive motion injuries such as carpal tunnel syndrome. Third, the rider""s high position produces a high center of gravity. Fourth, the rider can only inefficiently brake by pushing their hands against the tires or pushrims.
Advanced racing wheelchairs address these weaknesses by having a small diameter push rim for higher top speed, drive wheels that tilt out at the bottom for stability and an extended front wheel for balance. They are available from such firms as Invacare and Sunrise Medical.
Many attempts have been tried to change the basic wheelchair design for use by both physically challenged and able-bodied people. They usually fall into five main groups.
The first group uses levers. This group includes:
The second group has pushrims outside the two drive wheels. This group includes:
The third group has small handles outside the two drive wheels. This group includes:
The fourth group has direct drive handles inside the two drive wheels. This group includes:
The fifth group has hand cranks in front of the rider using a chain to drive one wheel in front. This group includes:
U.S. Pat. Nos. 4,682,784 and 4,705,284 both use dual reciprocating levers, and have several speeds. The required push/pull arm motion does not fully use the rider""s muscles (only the push moves the vehicle) and the high sitting position (about 13xe2x80x3) is unstable in turns.
U.S. Pat. No. 5,028,064 has a low, stable sitting position but still uses pushrims. Also, the rider can not easily move back and forth, thus preventing the abdominal and back muscles from helping propel the vehicle.
U.S. Pat. Nos. 3,563,568 and #4,727,965 have multiple speeds but also have pushrims and a high sitting position.
U.S. Pat. No. 5,037,120 has an efficient circular arm motion. However, a high sitting position, no brakes, and a rigid seat back hamper the rider""s performance. In addition, the this design has no coasting feature.
U.S. Pat. No. 4,758,013 has an efficient circular arm motion, brakes and reverse. However, a high sitting position, rigid seat back, and lack of easy frame adjustment also hamper the rider""s performance.
While U.S. Pat. Nos. 4,066,273 and 4,655,470 use the major muscle groups and have a low, stable seat, they have only one speed, cannot freewheel, and have no brakes. A similar device for children is commercially available through Lakeside Learning.
U.S. Pat. No. 4,109,927 has a front wheel that is driven by a chain connected to a hand cranked mechanism. The crank and front wheel look like the pedals and back wheel of a bicycle. This concept has an efficient circular arm motion, plurality of speeds and brakes. However, performance is hampered in this model because the rider cannot turn quickly. The front wheel is between the rider""s legs and so its turning angle is limited. Also, sudden stops can cause the rider""s chest to impact the chain sprocket. Similar devices are commercially available through Invacare, Sunrise Medical and Brike.
In addition, none of these patents show a seat that is comfortable for long periods. The seats are also not ventilated and provide no support for the rider as they rock back and forth. Moreover, most of these patents show a frame that cannot be adjusted for different sized riders.
It has been shown that the choices in outdoor exercise for physically challenged athletes have limitations. Furthermore, even able-bodied people have limited choices in physical exercise for the upper body. Millions of people run, bicycle, or rollerblade. However, all these exercises are for the lower body. There are few outdoor exercises for the upper body. Two choices are swimming and rowing, but lap pools and lakes are not readily available to most people. The arm-powered Land Rower will give able-bodied, as well as physically challenged, athletes a unique and well designed choice for upper body exercise.
The present invention is an arm-powered wheeled vehicle for outdoor, upper body exercise. Its main components are a substantially rectangular frame and two drive wheels, which are rotatably mounted along two opposite and parallel sides of the frame. Each side has a rotating handle driving an handle hub attached to a chain that in turn drives a ratcheting hub on the wheel. Different gears or leverages are incorporated in the rotating handle, the handle hub, the ratcheting hub, or any combination of the three. The rider uses a circular motion for propulsion by turning the rotating handle that subsequently drives the wheel. The vehicle has independent right and left brakes for the two drive wheels and a pivoting, adjustable third wheel mounted to the frame in front of the rider. A hammock like seat is attached to the front and rear of the vehicle and passes through a pivoting back support, giving the rider a comfortable, performance-enhancing position. In addition, the pivoting back allows for continuous support while the rider is moving back and forth while rotating the handle. The locations of the back, leg, and foot supports are adjustable. The vehicle can be configured for use by either physically challenged or able-bodied riders.
It is therefore a broad object of this invention to provide an arm-powered vehicle that can be used by both physically challenged and able-bodied riders.
It is another object of this invention to provide a vehicle that is propelled by the rider in an efficient way using the large muscles of the upper body in a full range of motion. This object can be accomplished by having the rider use a circular motion for propulsion with power being generated during the entire cycle.
It is another object of this invention to provide a propulsion method as described above that includes a means to change the gear ratio between the handles and the drive wheels to permit selection of optimum leverages for a particular situation.
It is another object to have a propulsion system that freewheels or coasts when the rider does not need to propel the vehicle.
It is another object to have right and left brakes that can be applied independently. The stopping forces should be transmitted to the frame rather than against the rider""s arms.
It is another object of this invention to provide a performance enhancing seat that is comfortable and lets the rider make efficient use of their upper body power.
It is another object of this invention to produce a stable vehicle by having a low sitting position.
It is another object to this invention to have a very maneuverable vehicle. Because it is stable and can pivot on one wheel, the Land Rower can safely have a short turning radius. This object is accomplished by having the rider change direction by using different power to the two drive wheels or by differential braking.
It is another object of this invention to have the vehicle be adjustable for different sized riders.
It is another object of this invention to have a vehicle that can be easily disassembled for transport.
It is another object of this invention to use existing technology so the Land Rower can be manufactured easily.
Some of the advantages of the present invention include: an efficient propulsion design; a multi-speed transmission; downhill coasting; comfortable, performance enhancing seat; stability and maneuverability; improved brakes; and an adjustable frame.
These, and other objects and advantages of the present invention, will become more apparent from a consideration of the detailed description of the preferred embodiments, when read in conjunction with the accompanying drawings.